What went wrong in the algebraic steps for ln rules?

In summary, the basic exponential log rules include product, quotient, power, and change of base rules. To simplify logarithmic expressions, one can use these rules as well as properties of logarithms. Logarithms and exponents are inverse operations and logarithms can be used to solve equations by simplifying and isolating the logarithm. The natural logarithm, ln(x), has a base of e and is commonly used in math and science.
  • #1
AnotherParadox
35
3
Given

ln(ab) = b⋅ln(a)

Then

ln(1x) = x⋅ln(1)

Also

ln(2x) = x⋅ln(2)

Say

ln(2x) = ln(1x)

Then Also

x⋅ln(2) = x⋅ln(1)

But, dividing both sides by x

ln(2) ≠ ln(1)

Similarly,

x⋅ln(2) = x⋅ln(1)

Dividing both sides by x and ln(2)

1 ≠ 0

But we know x = 0 as per the original statement.

The question then is which algebraic step(s) was(were) wrong, and why?
 
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  • #2
AnotherParadox said:
Say

##ln(2^x) = ln(1^x)##

this is not true if ##x\not= 0## and, if ##x=0## you can not divide by ##x## here:

AnotherParadox said:
Then Also

##x⋅ln(2) = x⋅ln(1)##

Ssnow
 
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FAQ: What went wrong in the algebraic steps for ln rules?

What are the basic rules for exponential and logarithmic functions?

The basic rules for exponential and logarithmic functions include the power rule, product rule, quotient rule, and change of base rule. The power rule states that when multiplying two exponential expressions with the same base, you can add the exponents. The product rule states that when raising an exponential expression to a power, you can multiply the exponents. The quotient rule states that when dividing two exponential expressions with the same base, you can subtract the exponents. The change of base rule allows you to rewrite logarithmic expressions in terms of a different base.

How do you simplify exponential and logarithmic expressions?

To simplify exponential and logarithmic expressions, you can use the basic rules mentioned above. You can also use the properties of logarithms, such as the product property, quotient property, and power property. Additionally, you can use the rules of exponents, such as the power of a power rule, power of a product rule, and power of a quotient rule.

What is the difference between exponential and logarithmic functions?

The main difference between exponential and logarithmic functions is the way they are written. Exponential functions are written in the form y = ab^x, where a is the initial value and b is the base. Logarithmic functions are written in the form y = log_b(x), where b is the base and x is the argument. Exponential functions represent rapid growth or decay, while logarithmic functions represent the inverse of exponential growth or decay.

How do you solve exponential and logarithmic equations?

To solve exponential and logarithmic equations, you can use the properties and rules mentioned above. You can also use the fact that logarithmic and exponential functions are inverses of each other. For example, if you have an equation in the form y = ab^x, you can rewrite it as log_b(y) = x and solve for x using the properties of logarithms. Similarly, if you have an equation in the form y = log_b(x), you can rewrite it as b^y = x and solve for x using the properties of exponents.

How are exponential and logarithmic functions used in real life?

Exponential and logarithmic functions are used in many real-life applications, such as population growth, compound interest, and radioactive decay. They are also used in fields such as economics, biology, and physics to model various phenomena. In finance, logarithmic functions are used to calculate the value of investments over time. In biology, exponential functions are used to model population growth. In physics, logarithmic functions are used to describe the intensity of sound and light waves.

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